Photographic printing material



Patented Sept. 12, 1944 T PHOTOGRAPHIC PRINTING MATERIAL William J.Kridel, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester,N. Y., a corporation of New Jersey No Drawing. Application March 14,1941, Serial No, 383,394

17 Claims.

This invention relates to photographic printing material and morparticularly to photographic material giving various degrees ofcontrast.

It is common practice to manufacture sensitive photographic emulsion ofdifferent kinds which give various degrees of contrast when submitted tothe same treatment, such various degrees of contrast being obtained bywell known technique in the manufacture of emulsions, such as byvariation in the grain size. Although it is possible to bring aboutvariation in contrast by suitable choice of development procedure (e. g.time or temperature variations) it is more useful to select the emulsionfor the purpose of obtaining the desired contrast, as this allows of theuse of standard times and temperatures of development which gives, amongother things, the most convenient and simplest processing conditions, aswell as a greater range of contrast (gradation). Thus, when makingprints of a number of different emulsion which works soft. If, on theother hand, it is desired to print from a-negative with but littlecontrast, thelightwhichacts upon the emulsion which works soft is cutoff by means of a filter permeable only to blue, and a normal picture isobtained by means of the emulsion which works hard.

variation of the above process involves the sensitization of thecontrasty chloride emulsion negatives differing widely in their contrastone usually takes say three or four different sensitive photographicpapers, each giving a different gradation, and selects therefrom thepaper giving the most suitable gradation for each particular negative.

It has been suggested to coat over one another sensitive layers whichwork as differently as possible in gradations and which act differentlyunder the action of the same kinds of light In this manner, a plurality'of gradations are made available in a single element, and to alimitedextent variations in contrast can be obtained by varying the exposuretime. Such a multi-contrast element, however, leaves much to be desired.

It has also been suggested to employ two different emulsions (eithercoated in layers upon one another or mixed together in one layer) whichgive different gradations under the same conditions of development.Thus, an emulsion which works hard and is sensitive to blue (such as a'silver chloride emulsion) can be mixed with an emulsion which works softand is sensitive to green (such as a spectrally sensitized silverbromide emulsion) to give a composite emulsion .capable of giving aplurality of contrasts. For example, if such a composite emulsion isexposed to light passing through a blue-green filter, the emulsion worksnormally'and is suitable for negatives of normal gradation. If, however,it is desired to print from anegative with strong contrasts, the lightwhich acts upon the emulsion which works hard is cut off by means of afilter permeable only to,green,

and a normal picture is obtained by means of the instead of the softerbromide emulsion, to the green portion of the spectrum,

'I have now foundrthat advantageous results can be obtained by coatingover one another two or more layers of silver halide emulsions ofdifferent contrast, the silver halide of the layers being ofsubstantially the same, instead of different chemical composition, thelayers being sensitive to different spectral regions. The image colorsgiven by the two silver halides of substantially the same chemicalcomposition can be more nearly alike than when different emulsions areemployed. By using substantially the same silver halides rather thandifferent ones, the time of development is more constant over the wholerange of contrasts when the same developing solution is used; indeed thenature of the developing solution is of less importance, so thatsatisfactory results can be obtained with a wide variety of developingsolutions. Moreover, if any addition (e. g. potassium bromide) is madeto the developing solution the effect thereof will be more nearly thesame over the whole range than when the emulsions involved aredifferent.

It is, accordingly, an object of my invention to provide a photographicprinting material which gives various degrees of contrast. A furtherobject is to provide a process for preparing such materials. Otherobjects will become apparent of my invention.

hereinafter.

In accordance with one embodiment of my invention, I position on oneside of a suitable support, such as of photographicpaper, of glass, ofcellulose acetate or nitrate film, or of polyvinyl acetal resin film, alayer of silver chloride emulsion of one contrast (gamma) over anotherlayer of silver chloride emulsion having a different contrast (gamma).

halide emulsion containing over of silver By the term silver chlorideemulsion," wherever used herein, I mean a silver chloride based on thetotal silver halide. It is the practice sometimes to incorporate a smallamount (several percent) of silver iodide or silver bromide in silverchloride emulsions, and such emulsions are included within the term ofthis embodiment I secure a difference in response to light of differentwave lengths between the aforesaid two layers by spectrally (optically)sensitizing one of the layers with a sensitizing dye. It is known thatthe maximum sensitivity of silver chloride emulsions is at about 390 mu.and that the sensitivity falls away sharply toward the longer wavelengths, so that for practical purposes chloride emulsions have nouseful sensitivity at wave lengths above 420 mu. In the presentembodiment of my invention, I have found it advantageous to sensitizeone of the chloride emulsions to a wave band between about 425 mu. andabout 600 mu. and such wave band can have a maximum at about 470 mu.,530 mu. or 570 mu, but advantageously not higher. If maximum sensitivityat 530 mu. obtains, the printing material can be handled and processedunder a safelight comprising light in the region from approximately 560'mu. upwards, i. e, an orange colored light. In the present embodiment ofmy. invention, the speed of the non-color sensitized emulsion to violetlight (i. e. the light to which the emulsion is most sensitive) may besmaller or greater than (for example one-half to one and a. quarter oreven two or three times) the speed of the colorsensitized emulsion toyellow light (minus blue light) and is also greater than (for exampleabout two to about ten times) the speed of the color sensitized emulsionto the same violet light.

In the present embodiment of my invention the desired range ofgradations can be obtained when making the exposures by using at one endof the range a filter transmitting light of a maximum of about 360 mu.(e. g. a Wratten No. 35 filter), but little useful light at wave lengthsabove about 440 mu., and at the other end of the range a filter of hightransmission at about 530 mu. or longer but little useful light at wavelengths below about 480 mu. (e. g. a Wratten No. 5 filter).

According to another form of the present embodiment of my invention twosilver chloride emulsion layers are employed each of which is spectrallysensitized to different wave bands. Advantageously the one emulsion isspectrally sensitized so as to have a maximum at about 460 mu. and theother is sensitized so as to have a maximum at about 530 mu. to 570 mu.-It is advantageous to employ a sensitizing dye which gives asensitization which falls away sharply toward the longer wave lengths sothat there is no useful sensitivity at about 600 mu. The dyes areadvantageously chosen so that there is no, or only a little, usefulsensitivity in both emulsions at the intermediate wave lengths betweenthe sensitizing maxima of the dyes; In this form of the invention thespeed of the first mentioned emulsion layer to blue light can be more orless (preferably between one-quarter and four times) than the speed ofthe second layer to yellow light (minus blue). Although the speeds ofthe two emulsions in the wavelength-range of their natural sensitivitiesare not highly important relative to the speeds of the emulsions at thesensitized maxima, it is nevertheless convenient that the emulsionsshould be so spectrally sensitized that the natural sensitivity remainsrelatively low; for example, one-fourth to one-tenth of the speeds atthe sensitized maxima.

In this form of the invention it is best to obtain the desired range ofgradation in making the exposure by using at one end of the range afilter transmitting light of a maximum of about 4'70 mu.. but littleuseful light at wave lengths below about 410 mu. and above about 500mu., and at the other end of the range a filter transmitting light of amaximum of about the same as the sensitized maximum of the secondmentioned emulsion, but little useful light at wave lengths below about500 mu. The printing material prepared according to this form of theinvention may be handled and processed under a safelight comprisinglight in the region from approximately 600 mu. upwards, i. e. orange orred light.

In the first of the above forms of my invention it is preferred toemploy for the emulsion giving the higher gradation the one which hasthe sensitivity at the higher wave lengths. It is also preferred to makethe speeds of the two emulsions about the same in the spectral regionsemployed for exposure purposes. The gradation of the emulsion giving thelower contrast can, for example, be between 0.8 and 1.8, while thegradation of the emulsion giving the higher contrast can be at least twoand one-half times greater.

The following example will serve to illustrate the present embodiment ofmy invention:

Example I Two emulsion layers were coated upon a suitable photographicpaper support. The two layers comprised respectively a low contrastsilver chloride developing-out emulsion sensitized with 3- ethyl-5-(1-methyl-2 (1) -B naphthoxazolylidene) -rhodanine at a concentration of100 mg. per 1000 grams of silver nitrate used in the preparation of theemulsion, and a high contrast silver chloride developing-out emulsionsensitized with 5 (2 ethyl-1-benzoxazolylidine-ethylidene)-3- ethylrhodanine at the same concentration. If desired the concentrations ofthese dyes can be varied over a range of about 25 to 200 mg. In thecoating of the paper the low contrast chloride emulsion is first coatedon the paper in the range of normal thickness of paper coatings andabove it is coated the high contrast chloride emulsion at about the samethickness. The filters which should be employed with a printing materialprepared in this manner are the Wratten No. 34 to obtain low contrastand the Wratten No. 12 for high contrast. Mixtures of exposuresemploying these two filters will, of course, produce intermediatecontrasts.

In accordance with a second embodiment of my invention I position on oneside of a suitable support a layer of silver chloro-bromidedevelopingout emulsion of one contrast over another layer of silverchloro-bromide developing-out emulsion having a different contrast. Bythe term silver chloro-bromide emulsion" wherever used herein I mean asilver halide emulsion containing over 10% and less than (but preferablyover 30% and less than 70%) of silver chloride based on the total silverhalide. It is desirable that the silver chloride content of the twoemulsions should not differ by more than 25% and preferably not morethan 10%. It is the practice sometimes to add a small amount of silveriodide to silver chloro-bromide emulsions and such emulsions areincluded within the terms of this embodiment ogtmy invention.

I have found hat the best results are obtained by using for thesensitive material in the present form of my invention, a silverchloro-bromide emulsion layer of relatively high gradation sensitized tothe green, or yellow, or yellow-green, region of the spectrum, with asilver chloro-bromide emulsion layer of relatively low gradation but notspectrally sensitized. On such a material I print from negatives of highcontrast by means of blue light, from negatives of medium contrast bymeans of white light (tungsten) or mixed blue and yellow to green lightand from negatives of low contrast by means of suitable light in theminus blue part of the spectrum. In order to produce a sensitivematerial of the greatest convenience and simplicity we have found thatthe coated emulsions and the spectrally sensitizing dye should be sochosen that the speed of the non-spectrally sensitized blue-sensitiveemulsion layer to blue light (i. e. the light to which the emulsion ismost sensitive) should be at least 1.8 (and preferably at least twice)the speed of the spectrally (color) sensitized emulsion layer to thesame blue light. The speed of the spectrally sensitized emulsion layerin the green to yellow should be not less than one-third and may be upto one and one-fourth or even two or three times the speed ofthenon-spectrally sensitized emulsion layer in the blue region. Thegradation of the non-spectrally sensitized emulsion should be between0.8, and 1.8, while the gradation of the spectrally sensitized emulsionlayer in the yellow green region of the spectrum should be at least 2.5times greater.

In accordance with a third embodiment of my invention I position on oneside of a suitable support a layer of silver bromide emulsion of onecontrast over another layer of silver bromide emulsion having adifferent contrast. The bromide emulsions of the present form of myinvention advantageously should not contain any appreciable quantity ofchloride, although it is possible to use up to of silver chloride basedon the total weight of silver halide without markedly noticeableefiects. It is the practice sometimes to add a small amount of silveriodide to silver bromide emulsions and such emulsions are includedwithin the terms of the present embodiment of my invention. In thepresent form of my invention both emulsions can be made more highlysensitive then when one or both of the emulsions are wholly silverchloride or contain an important proportion of silver chloride as in thecase in the so-called chloro-bromide emulsions.

In one form of this third embodiment of my invention I employ one layerof asilver bromide emulsion of relatively high gradation sensitized tothe green or yellow or yellow-green region of the spectrum, with a layerof a silver bromide emulsion of relatively low gradation but notspectrally .sensitized. On such a two-emulsion layer material I printfrom negatives of high contrast by means of blue light, from negativesof medium contrast by means of white light (tungsten) or mixed blue andyellow to green light, and from negatives of low contrast by means ofsuitable light in the minus blue part of the spectrum. In order toproduce a sensitive photographic element of the greatest convenience andsimplicity I have found that the coated emulsions and the spectrallysensitizing dye should be so chosen that the speed of the non-spectrally(non-color) sensitized emulsion to blue light (i. e. the light to whichthe emulsion is most sensitive) should be at least 1.8 (and preferablyat least twice) the speed 01 the color sensitized emulsion to the sameblue light. The speed of the spectrally sensitized emulsion in the greento yellow region should be between one-third and one and one quartertimes the speed of the non-spectrally sensitized emulsion in the blueregion. The gradation of the non-spectrally sensitized emulsion shouldbe between 0.8 and 1.8 while the gradation of the spectrally sensitizedemulsion in the yellow to green region of the spectrum should be atleast 2.5 times greater.

The following example will serve to illustrate this third embodiment ofmy invention.

Example II cyanine iodide, a speed in the blue region of 2.0

' and a speed in the green of 5.6 and a gradation difierent colorexposure lights.

of 5.4. This emulsion is used for the under layer. For the upper layersuch an emulsion is prepared which gives a speed in the blue region of5.4 and a gradation of 1.5. This two-emulsion layer material is exposedby tungsten light through negatives of low gamma through a Wratten No. 5filter, through negatives of high gamma through a Wratten No; 47A filterand through negatives of medium gamma through no filter or through aWratten K1 filter. An advantage of coating the emulsions in separatelayers (two or more) as is done in accordance with any of theembodiments of m invention is that wandering (diffusing) of thesensitizing dyes from one layer to another can be fairly readilyovercome. For example, any such tendency can be ofiset by coating athin, intermediate, clear gelatin layer between the emulsion layers andincorporating in the intermediate layer substances which are capable ofretarding diffusing of the sensitizing dyes, whereby any sensitizing dyewhich wanders into the layer will besubstantially prevented from passingthrough a layer into the next emulsion layer. Such an intermediate layermay also contain a filter dye to assist in obtaining the desired rangeof contrasts with Preferably the filter dye should be one that becomesdecolorized in the processing baths. I

If there is any tendency for the sensitizing dye employed in oneemulsion layer to Wander into the other emulsion layer it may beadvisable to offset the effect produced thereby by using emulsions ofmore widely diiTering gradations. For example, the higher one may beincreased to such an extent that it is at least 3.5 or even at least 4.5times greater-than the gradation of the other em'ulsion. Usually thegradation of the optically sensitized emulsion giving the highergradation will not be more than about 7 or 8.

Instead of coating the two emulsions in layers, the emulsions can bemixed together before applying to a'support. Such mixed emulsions havethe advantage that a printing material can be produced therefrom with atleast one less coating operation, than when superimposed layers of thetwo emulsions are employed. Moreover, from such mixed emulsions printingelements can be produced. the over all weight of which is less than thatof an element produced with layers of emulsions. Such lighter weightelements are less brittle and have a lesser tendency to curl than theheavier layered elements.

Prepared in accordance with any of the em bodiments of my invention, Ihave found that the ratio of silver between the contrasty and softemulsions is advantageously 1:1, i. e. the moles 'United States Patent2,331,660, dated October 12,

1943), or substantially water-insoluble metal compounds, such as oxidesand hydroxides, can

be incorporated in the emulsions alone or in conjunction with the aboveresins, or substantially water-insoluble metal salts of the above resinscan be incorporated in the emulsions (see the copending application ofEdward B. Knott, Serial No. 391,375, filed May 1, 1941, now UnitedStates Patent 2,336,260, dated December 7, 1943.

In practicing my invention, however, by far'the best results areobtained by using sensitizing dyes which are inherently non-diffusing.Non-diffusing sensitizing dyes which sensitize to the green are to befound in the thia-2'-cyanine, the benzothia-2-cyanine, theselena-2'-icyanine, the 2,2- cyanine, the thiazolo-2'-cyanine and thedibenzoxacarbocyanine classes of dyes. Non-diffusing dyes whichsensitize to longer wavelengths are to be found in thedibenzothiacarbocyanine, the 5,5-dichlorothiacarbocyanine, the5-chloroth.ia carbocyanine, the 5-chlorothiabenzothiacarbocyanine, the5,5-dichloroselenacarbocyanine, the 5-chloroselenacarbocyanine and the5-chloro-' selenabenzothiacarbocyanine classes of dyes. Non-diffusingsensitizing dyes are also to be found among the simple merocyanines, themerocarbocyanines and the merodicarbocyanines containing on the onehand-a 3-alkylrhodanine, a 3-arylrhodanine or a 2-diarylamino-4(5)-thiazolone nucleus and on the other hand a benzoxazole, abenzothiazole, a benzaselenazole, a naphthoxazole, a naphthothiazole, ora simple thiazole nucleus (1. e., a thiazole nucleus devoid of afused-on aromatic ring, e. g. 4-methylthiazole and 4-phenylthiazole).Merocyanine dyes which contain a long chain organic group (e, g. a 3-heptyl-1-phenyl-2-thiohydantoin nucleus) and which are especiallyresistant to diffusion are described in the copending application ofLeslie G. S. Brooker, Serial No. 321,730, filed March 1, 1940, nowUnited States Patent 2,282,116, dated May 5, 1942.

The speeds referred to herein are measured by taking the exposurenecessary to give a. density of 1.0. The contrasts are expressed asgamma or maximum gradient.

What I claim as myinvention and desire to be secured by Letters Patentof the United States is:

1. A photographic printing material for the production of images ofdifierentcontrast from black-and-white images, under the same conditionsof development, comprising a layer of a the emulsion, and a silverbromide emulsion in which the" weight of silver bromide is at least90per cent of the total silver halide in the emulsion, withanotherphotographic silver halide emulsion of the same species buthaving a contrast at least 2.5 times as great as the contrast of thefirst emulsion, the ratio of silver between the emulsion of lowercontrast and the emulsion of higher contrast being such that the twoemulsions can be developed, under the same conditions of development, tomaximum densities of the same order, at least one of the emulsions beingsensitized with a sensitizing dye so that the emulsions are sensitive todifierent spectral regions, both emulsions being free from dyes otherthan sensitizing dyes.

2. A photographic printing material for the production of images ofdifierent contrast from black-and-white images, under the sameconditions of development, comprising a layer of a composite of aphotographic silver halide emulsion having a contrast of 'at least about0.8 selected from the group consisting of the three species: a silverchloride emulsion in which the weight of silver chloride is more than 90per cent of the total silver halide in the emulsion, a silverchlorobromide emulsion in which the weight of silver chloride is frommore than ,30 per cent to less than 70 per cent of the total silverhalide in theemulsion, and a silver bromide emulsion in which the weightof silver bromide is at least 90 per cent of the total silver halide inthe emulsion, with another photographic silver halide emulsion of thesame species but having a contrast at least 2.5 times as great as thecontrast of the first emulsion, the ratio of silver between the emulsionof lower contrast and the emulsion of higher contrast being about 1:1,at least one of the emulsions being sensitized with a sensitizing dye sothat the emulsions are sensitive to different spectral regions, bothemulsions being free from dyes other than sensitizing dyes.

3. A photographic printing material fo the production of'images ofdifferent contrast from black-and-white images, under the sameconditions of development, comprising a layer of a composite of aphotographic gelatino-silverhalide developing-out emulsion having acontrast I of at least about 0.8 selected from the group consisting ofthe three species: a silver 'chloride emulsion in which the weight ofsilver chloride is more than 90 per cent of the total silver halide inthe emulsion, a silver chlorobromide emulsion in which the weight ofsilver chloride is from more than 30 per cent to less than 70 per centof the total silver halidein the emulsion, and a silver bromide emulsionin which the weight of silver bromide is at least 90 per cent of thetotal silver halide in the emulsion, with another photographic silverhalide emulsion of the same species,

the second emulsion having a contrast at least- 2.5 times as great asthe contrast of the first emulsion, the ratio of silver between theemulsion of the lower contrast and the emulsion of higher contrast beingsuch that the two emulcomposite of a photographic silver halide emulsionhaving a contrast of at least about 0.8 selected from the groupconsisting of the three species: a silver chloride emulsion in which theweight of silver chloride is more than 90 per cent of the total silverhalide in the emulsion, a silver chlorobromide emulsion in which theweight of silver chloride is from more than 30 per cent to less than percent of the total silver halide in sions can be developed, under thesame conditions of development, to maximum densities of the 1 sameorder, at least one of the emulsions being sensitized with a sensitizingdye so that the emulsions are sensitive to diiferent spectral regions,both emulsions being free from dyes other than sensitizing dyes.

4. photographic printing material for the production of images ofdifferent contrast from black-and-white images, under the sameconditions of development, comprising a layer or a composite of aphotographic gelatino-silverhalide developing-out emulsion having acontrast of at least about 0.8 selected, from the group consisting ofthe three species: a silver chloride emulsion in which the weight ofsilver chloride is more than 90 per cent of the total silver halide inthe emulsion, a silver chlorobromide emulsion in which the weight ofsilver chloride is from. more than 30 per cent to less than '70 per centof the total silver halide in the emulsion, and a silver bromideemulsion in which the weight of silver bromide is atleast 90 per centerthe total silver halide in the emulsion, with another photographicsilver halide emulsion of thesame species, the second emulsion having acontrast at least 2.5 times as great as the contrast of the firstproduction of images of diner contrast from black-and-white images,'und',th same'conditionsof development, comprising layer of a composite of aphotographic gelatino-silverhalide developing-out emulsion having acontrast of at least about 0.8 selected from the group consistingof'th'e three species: a silver chloride emulsion in which the weight ofsilver chloride is more than 90 per cent of the total silver-halide inthe emulsion, asilver chlorobromide emulsion in which the weight ofsilver chloride is from more than 30 per cent to less than 70 per centof the total silver halide in the emulsion, and a silver bromideemulsion in which the weight of silver bromide is at least 90 per centof the total silver halide in the emulsion, with another photographicsilver halide emulsion of the same species, the second emulsion having acontrast at least 2.5 times as great as the contrast of the firstemulsion, the ratio of silver between the emulsion of lower contrast andthe emulsion of higher contrast being such that the two emulsions can bedeveloped, under the same conditions of development, to maximumdensities of the same order, at least one ofthe emulsions beingsensitized with asensitizing dye so that the emulsions are sensitive to'difierent spectral regions, the speed of the emulsion of lower contrastto light to which the emulsion is inherently most sensitive being fromabout two to about ten times the speed of the emulsion of highercontrast to the same light, both'emulsions being free from dyes otherthan sensitizing dyes.

6. A photographic printing material for the production of images ofdifferent contrast from black-and-white images, under the sameconditions of development, comprising a. layer of a composite of aphotographic gelatino-silverhalide developing-out emulsion having acontrast of at least about 0.8 selected from the group consisting of thethree species: a silver chloride emulsion in which the weight of silverchloride is more than 90 per cent of the total silver halide in theemulsion, a silver chlorobromide emulsion in which the weight of silverchloride is from more than 30 per cent to less than '70 per cent of thetotal silver halide in the emulsion, and a silver bromide emulsion inwhich the weight of silver bromide is at least 90 per cent of the totalsilver halide in the emulsion, with another I having a contrast of'atleast about 0.8 in which photographic silver halide emulsion of the samespecies, the second emulsion having a contrast at least 2.5 times asgreat as the contrast of the first emulsion, the'ratio of silver betweenthe emulsion of lower contrast and the emulsion of higher contrast beingabout 1:1, at least one of the emulsions being sensitized with asensitizing dye so that the emulsions are sensitive to differentspectral regions, the speed of the emulsion of lower contrast tolight towhich the emulsion is inherently most sensitive being from about two toabout ten times the speed of the emulsion of higher contrast to the samelight, both emulsions being free from dyes other than sensitizing dyes.

7. A photographic printing material for. the production of images ofdifierent contrast from black-and-white images, under the sameconditions of development, comprising a support bearing on one side acomposite of a photographic gelatino-silver-chloride developing-outemulsion having a contrast of at least about 0.8 in which the weight ofsilver chloride is more than 90 per cent of the total silver halide inthe emulsion with another photographic gelatino-silver-chloridedeveloping-out emulsion in which the weight of silver chloride is morethan 90 per cent of the total silver halide in the emulsion coated 8. Aphotographic printing material for the production of images of diiierentcontrast from blaok-and-white images, under the same conditions ofdevelopment, comprising a support bearing on one side a composite of a;photographic gelatino-silver-chloride developing-out emulsion the weightof silver chloride is more than 90 per cent of the total silver halidein the emulsion and another photographic gelatino-silver-chloridedeveloping-out emulsion in which the weight of silver chloride is morethan 90 per cent of the total silver halide in the emulsion coated uponthe first emulsion and having a contrast at least 2.5 times as great asthe contrast of the first emulsion, the ratio of silver between theemulsion of lower contrast and the emulsion of higher contrast beingabout 1:1, at least one of the emulsions being sensitized with asensitizing dye so that the emulsions are sensitive to differentspectral regions, both emulsions being free from dyes other thansensitizing dyes.

9. A photographic printing material for the production of images ofdifferent contrast from black-and-white images, under the sameconditions of development, comprising a layer of a composite of aphotographic gelatino-sllver-chloride developing-out emulsion havinga'contrast of at least about-0.8 in which the weight of silver chlorideis more than per cent of the total silver halide in the emulsion withanother photographic gelatino-silver-chloride developing-out emulsion inwhichthe weight of silver chloride is more than 90 per cent of the totalsilver halide in the emulsion having a contrast at least 2.5

times as great as the contrast of the first emulsion, the ratio ofsilver between the emulsion of lower contrast and the emulsion of highercontrast being such that the two emulsions can be developed, under thesame conditions of development, to maximum densities of the same order,at least one of the emulsions being sensitized with a sensitizing dye sothat the emulsions are sensitive to different spectral regions, thespeed of the emulsion of lower contrast to violet light being from abouttwo to about ten times the speed of the emulsion of higher contrast tothe same light, both emulsions being free from dyes other thansensitizing dyes.

10. A photographic printing material for the production of images ofdifierent contrast from black-and-white images, under the sameconditions of development, comprising a layer of a composite of aphotographic gelatino-silver-chloride developing-out emulsion having a.contrast of at least about 0.8 in which the weight of silver chloride ismore than 90 per cent of the total silver halide in the emulsion withanother photographic gelatino-silver-chloride developing-out emulsion'inwhich the weight of silver chloride is more than 90 per cent of thetotal silver halide in the emulsion having a contrast at least 2.5 timesas great as the contrast of the first emulsion, the ratio of silverbetween the emulsion a of lower contrast and the emulsion of highercontrast being about 1:1, at least one of the emulsions being sensitizedwith a sensitizing dye so that the emulsions are sensitive to differentspectral regions, the speed of the emulsion of low contrast to violetlight being from about two to about ten times the speed of the emulsionof higher contrast to the same light, both emulsions being free fromdyes other than sensitizing dyes.

11. A photographic printing material for the production of images ofdiflerent contrast from black-and-white images, under the sameconditions of development, comprising a support bearing on one side acomposite of a photographic gelatino-silver-chloride developing-outemulsion having a contrast of at least about 0.8 in which the weight ofsilver chloride is more than 90 per cent of the total silver halide inthe emulsion and another photographic gelatino-silver-chloridedeveloping-out emulsion in which the weight of silver chloride is morethan 90 per cent of the total silver halide in the emulsion coated uponthe first emulsion and having a contrast at least 2.5 times as great asthe contrast of the first emulsion, the ratio of silver between theemulsion of lower contrast and the emulsion of higher contrast beingsuch that the} two emulsions can be developed, under the same conditionsof development, to maximum densities of the same order, the emulsion oflower contrast being free from sensitizing dyes and the emulsion ofhigher contrast being sensitized with a sensitizing dye so as to have amaximum of spectral sensitivity at from about 470 mu. to about 530 mu.,the speed of the emulsion of lower contrast to violet light being fromabout two to about ten times the speedof the emulsion of higher contrastto the same violet light, both'emulsions being free from dyes other thansensitizing dyes.-

12. A photographic printing material for the production of images ofdifierent contrast from black-and-white images, under the sameconditions of development, comprising a support bearing on one side acomposite :of a photographic gelatino-silver-chloride developing-outemulsion having a contrast of at least about 0.8 in which the weight ofsilver chloride is more than per cent of the total silver halide in theemulsion and another photographic gelatino-silver-chloridedeveloping-out emulsion in which the weight of silver chloride is morethan 90 per cent of the total silver halide in the emulsion coated uponthe first emulsion and having a contrast at least 2.5 times as great asthe contrast of the first emulsion, the ratio of silver between theemulsion of lower contrast and the emulsion of higher contrast beingabout 1:1, the emulsion of lower contrast being free from sensitizingdyes and the emulsion of higher contrast being sensitized with asensitizing dye so as to have a maximum of spectral sensitivity at fromabout 470 mu. to about 530 mu., the speed of the emulsion of lowercontrast to violet light being from about two to about ten times thespeed of the emulsion of higher contrast to the same violet light, bothemulsions being free from dyes other than sensitizing dyes.

13. A photographic printing material for the production of images ofdifferent contrast from black-and-white images, under the sameconditions of development, comprising a support bearing on one side acomposite of a photographic gelatino silver chlorobromide developing-'out emulsion having a contrast of at least about 0.8 in which theweight of silver chloride is from more than 30 per cent to less than '70per cent of the total silver halide in the emulsion and anotherphotographic gelatino-silver-chlorobromide developing-out emulsion inwhich the weight of silver chloride is from more than 30 per cent toless than 70 per cent of the total silver halide in the emulsion coatedupon the first emulsion and having a contrast at least 2.5

times as great as the contrast of the first emulsion, the ratio ofsilver between the emulsion of lower contrast and the emulsion of highercohtrast being such that the two emulsionscan be developed, under'thesame conditions of development, to maximum densities of the same order,at least one of the emulsions being sensitized with a sensitizing dye sothat the emulsions are sensitive to difierent spectral regions, bothemul- Zions being free from dyes other than sensitizing yes.

14. A photographic printing material for the production of images ofdifferent contrast from black-and-white images, under the sameconditions of development, comprising a support hearing on one side acomposite of a photographic gelatino silver chlorobromide developing outemulsion having contrast of at least about 0.8 in which the weight ofsilver chloride is from more than 30 per cent to less than 70 per centof the total silver halide in the emulsion and another photographicgelatino-silver-chlorobromide developing-out emulsion in which theweight of silver chloride is from more than 30 per cent to less than 70per cent of the total silver halide in the emulsion coated upon thefirst emulsion and having a contrast at least 2.5 times as great as thecontrast of the first emulsion, the ratio of silver between the emulsionof lower contrast and the emulsion of higher contrast being about 1:1,at least two of the emulsions being sensitized with a sensitizing dye sothat the emulsions are sensitive to different spectral regions, bothemulsions being free from dyes other than sensitizing dyes.

15. A photographic printing material for the production of images ofdifierent contrast from black-and-white images, under the sameconditions of development, comprising a support bearing on one side acomposite of a photographic gelatino silver chlorobromide developing outemulsion having a contrast of at least 0.8 in which the weight of silverchloride is from more than 30 per cent to less than 70 per cent of thetotal silver halide in the emulsion and another photographicgelatino-silver-chlorobromide developing-out emulsion in which theweight of silver chloride is from more than 30 per cent to less silverbetween the emulsion of lower contrast and the emulsion of highercontrast being such that the two emulsions can be developed, under thesame conditions of development, to maximum densities of the same order,the emulsion of lower contrast being free from sensitizing dyes and theemulsion of higher contrast being sensi tized with a sensitizing dye soas to have a maxi- -mum of spectral sensitivity in the yellow-greenregion of the spectrum, the speed of the emulsion of lower contrast toblue light being at least about 1.8 times the speed of the emulsion ofhigher contrast to the same blue light, both emulsions being free fromdyes other than sensitizing dyes.

16. A photographic printing material for the production of images ofdifferent contrast from black-and-white images, under the sameconditions of development, comprising a support hearing on one side acomposite of a photographic gelatino silver chlorobromide developing outemulsion having a contrast of at least about 0.8 in which the weight ofsilver chloride is from more than 30 per cent to less than '70 per centof the total silver halide in the emulsion and another photographicgelatinol-silver-chlorobro- 40 mide developing-out emulsion in which theweight of silver chloride is from more than 30 per cent to less than percent of the total silver halide in the emulsion coated upon the firstemulsion and having a contrast at least 2.5 40

times as great as the contrast of the first emulsion; the ratio ofsilver between the emulsion of higher contrast being about 1:1, theemulsion of lower contrast being free from sensitizing dyes and'theemulsion of higher contrast being-sensitized with a sensitizing dye soas to have a maximuin of spectral sensitivity in the yellow-green regionof the spectrum, the speed of the emulsion of lower contrast to bluelight being at least about 1.8 times the speed of the emulsion of highercontrast to the same blue light, both emulsions being free from dyesother than sensitizing dyes.

1'7. A photographic printing material for the production of images ofdifferent contrast from black-and-white images, under the sameconditions of development, comprising a layer of a composite of aphotographic gelatino-silverhalide developing-out emulsion having acontrast of at least about 0.8 selected from the group consisting of thethree species: a silver chloride emulsion in which the weight of silverchloride is more than per cent of the total silver halide in theemulsion, a silver chlorobromide emulsion in which the weight of silverchloride is from more than 30 per cent to less than 70 per cent of thetotal silver halide in the emulsion, and a silver bromide emulsion inwhich the weight of silver bromide is at least 90 per cent of the totalsilver halide in the emulsion, with another photo'graphic silver halideemulsion of the same species, the second emulsion having a contrast atleast 2.5times as great as the contrast of the first emulsion, the.ratio of silver between the emulsion of higher contrast being such thatthe two emulsions can be developed, under the same conditions ofdevelopment, to maximum densities of the same order, the emulsion oflower contrast being free from sensitizing dyes and the emulsion ofhigher contrast being sensitized with a. sensitizing dye so as to have amaximum of spectral sensitivity at a wavelength longer than the maximumof spectral sensitivity of the emulsion of higher contrast, the speed ofthe lower contrast emulsion to light to which it is inherently mostsensitive being substantially greater than the speed of the emulsion ofhigher contrast to the same light, both emulsions being free from dyesother than sensitizing dyes.

WILLIAM J. KRIDEL.

